Useful layers may be produced for example on the basis of nanoparticles. Nanoparticles are particles which have a particle size in the nanometer range (1 nm to 1000 nm) and usually display chemical and physical properties which differ from those of their particle material as such. The different properties of the nanoparticles are based on the relatively great outer surface area in relation to their volume.
In addition, it is known for example from European laid-open patent application EP 1 215 306 that protective MCrAlY layers are used as a protective coating for turbine blades. Furthermore, it is known from EP 1 632 589 A2 that, after the turbine blades reach the end of their useful life, such protective MCrAlY layers can be removed from the blade, for example by means of an electrochemical process. The blades from which the coating has been removed can subsequently be re-coated and passed on for a further product life cycle.
A method by which superhard cutting materials can be obtained from a tool coating is known from DD 235 889 A1. When the tool has reached the end of its useful life, for this purpose it is subjected to an electrochemical treatment in which the metallic matrix material is dissolved, thereby releasing the superhard cutting materials. Therefore, after filtering and drying, the layer constituent of the superhard cutting materials is available for further coating processes.